This invention relates generally to a material handling apparatus and more specifically to a material handling apparatus having at least one rotatable boom section.
One known material handling apparatus includes a base boom section which is mounted on a cradle for rotational or tilt movement about a central longitudinal axis of the boom section. A trunnion type bearing assembly is provided between the end wall of the base boom section and the cradle to permit rotation of the base boom section in the cradle and to retain the base boom section against axial movement relative to the cradle. This known material handling apparatus includes a hydraulic motor which is connected to the front of the cradle to drive a gear segment carried by the base boom section. A fluid passage arrangement has been provided in association with the trunnion bearing between the end wall of the cradle and the end wall of the base boom section to conduct hydraulic fluid to the piston and cylinder assembly for moving the inner boom section relative to the base boom section.
There are many other known types of material handling devices having rotatable boom sections. Some of these known devices are disclosed in U.S. Pat. Nos. 3,700,126; 3,224,608; 3,042,234; and 2,541,045. In addition to these prior art material handling devices, a material handling apparatus having a base boom section which is rotated under the influence of a cradle mounted tilt motor is disclosed in copending application Ser. No. 512,249 filed Oct. 4, 1974 by John W. Gano and entitled "Material Handling Apparatus". Although these known material handling devices have been more or less satisfactory in their operation, it is desirable to reduce the cost of manufacturing of these material handling devices as much as possible, particularly when they are to be subjected to relatively light operating loads.